mapped_struct.py 文件源码

def get_packable(self, packer, padding, obj, offs = 0, buf = None, idmap = None, implicit_offs = 0):
        if idmap is None:
            idmap = {}
        baseoffs = offs
        if buf is None:
            buf = self._pack_buffer
        has_bitmap, none_bitmap, present_bitmap = self._get_bitmaps(obj)
        fixed_present = present_bitmap & self._fixed_bitmap
        size = packer.size
        offs += size + padding
        if offs > len(buf):
            raise struct.error('buffer too small')
        packable = [
            has_bitmap,
            none_bitmap,
        ]
        packable_append = packable.append
        idmap_get = idmap.get
        slot_types = self.slot_types
        alignment = self.alignment
        for i,slot in enumerate(self.slot_keys):
            mask = cython.cast(cython.ulonglong, 1) << i
            if present_bitmap & mask:
                val = getattr(obj, slot)
                if fixed_present & mask:
                    packable_append(val)
                else:
                    val_id = id(val)
                    val_offs = idmap_get(val_id)
                    if val_offs is None:
                        idmap[val_id] = ival_offs = offs + implicit_offs
                        offs = slot_types[slot].pack_into(val, buf, offs, idmap, implicit_offs)
                        padding = (offs + alignment - 1) / alignment * alignment - offs
                        offs += padding
                    else:
                        ival_offs = val_offs
                    packable_append(ival_offs - baseoffs - implicit_offs)

        padding = (offs + alignment - 1) / alignment * alignment - offs
        offs = offs + padding
        if offs > len(buf):
            raise struct.error('buffer too small')
        return packable, offs